Chair

ABSTRACT

The present invention relates to a chair having a center of gravity that can be intentionally made to adopt an unstable state when the chair is sat upon. The objective of the present invention is to provide a self-standing type chair that is unstable when in use and that automatically stands by itself using auxiliary legs when not in use, and that is convenient to handle. The main feature of the present invention is that, in order for a chair that is unstable when in use to be self-standing when not in use, auxiliary legs ( 14   a   , 14   b ), other than a main leg, form new points of contact with a floor or ground surface by utilizing the action of an urging means and a driving force transmission means that accompanies the removal of weight from the chair by a user.

TECHNICAL FIELD

The present invention relates to a chair, particularly to a chair having a center of gravity that can be intentionally made to adopt an unstable state when in use, and that automatically stands by itself using auxiliary legs when not in use, this self-standing type chair is convenient to handle.

BACKGROUND OF THE INVENTION

Generally, chairs that are configured by metal, high-polymer materials, wood, or components including a combination thereof are manufactured and used for the purpose of supporting the bodies of those sitting thereon, thereby reducing the burden of the used muscles particularly centered on the inferior limbs. Specifically, chairs are manufactured and used for the purpose of stabilizing the posture of those sitting thereon together with their center of gravity by supporting their weight via the buttocks, back, arms, seating face, backrest, and armrests of the chair.

Moreover, this seating face, backrest, and armrests of the chair are supported by the legs of the chair, with the front ends of the legs maintaining the self-standing state of the chair by coming into contact with a floor or ground surface on at least three points.

On the other hand, a chair exists which, despite allowing the seating face to support the buttocks of the person sitting thereon, is unstable for the purpose of promoting health and activating the brain of the user of the chair by inducing muscular exercises centered on the inferior limbs via making the center of gravity unstable, forcing the user to maintain their balance using both inferior limbs so as not to fall, and increasing stimulation to the brain. As such an example, Patent Document 1 discloses a chair that cannot self-stand with one leg attached to the lower side of the seating face thereof.

The features of such a chair that is unstable when in use are as follows. A normal chair stably supports the weight of a person sitting thereon by at least three or more points of contact of the legs with a floor or ground surface. In contrast, according to a chair that is unstable when in use, namely, the abovementioned chair with only one leg or a chair with two legs, as there are at most two points of contact of the legs with a floor or ground surface, the chair has to support the other lacking points of contact via the inferior limbs of the person sitting thereon. As a result, the person sitting on the chair that is unstable when in use is required to maintain his or her balance so as not to fall by coming into contact with a floor or ground surface using both or either one of their inferior limbs.

Accordingly, as these chairs that are unstable when in use cannot stand by themselves without auxiliary legs compensating for balance, the chair is required to be laid on a floor or ground surface, to be set against something, or be hung on something, thereby necessitating locations for laying, setting, or hanging the chair, along with a need to prepare tools for laying, setting, or hanging the chair and labor for handling the tools.

For reference, there is an example of the balance ball, the user maintaining his or her balance in order to resolve the unstable state when in use a spherical balloon as a chair; however, it should be noted that the balance ball occupies a set location, with the diameter thereof defined as its width, and further, the balance ball easily rolls due to lateral force as it lacks stability, making it difficult to handle.

PRIOR ART DOCUMENT(s) Patent Document

Patent Document 1: JP 2009-125569

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The problem solved by the present invention is to allow the easy handling of a chair that has legs having two or less points of contact of the legs with a floor or ground surface when in use by having the chair stand by itself via automatically setting auxiliary legs when not in use.

Means for Solving the Problems

The main feature of the present invention is that, in order for a chair that is unstable when in use to be self-standing when not in use, auxiliary legs, other than a main leg, form new points of contact with a floor or ground surface by utilizing the action of an urging means such as a coil spring and a driving force transmission means that transmits the driving force of the urging means when the weight of the user is not loaded onto the seating face of the chair.

The main feature of the present invention is a chair which is unstable when in use and to be self-standing when not in use. When the weight of the user is not loaded onto the seating face of the chair, and which is stood by the auxiliary legs, other than a main leg, form new points of contact on a floor or ground surface. This action is made by an urging means such as a coil spring, through a driving force transmission means.

Effects of the Invention

Because a chair that is unstable when in use with legs having two or less points of contact with a floor or ground surface when in use cannot stand by itself when not in use without auxiliary legs or projections that compensate for the lack of another point of contact, the chair must be laid on a floor or ground surface, be set against something, or be hung on something. The present invention is advantageous in that it resolves the problems caused by controlling of the positions for laying, setting or hanging the chair, and tools required for laying, setting or hanging the chair.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an example of the chair according to the present invention, with FIG. 1(a) illustrating an example having one main leg and FIG. 1(b) having two main legs.

FIG. 2 is a drawing illustrating an example of the chair according to the present invention having one main leg provided with auxiliary legs, with FIG. 2(a) illustrating the state when the chair is not in use and FIG. 2(b) illustrating the state when the chair is in use.

FIG. 3 is a cross-sectional view illustrating an example of the configurations of an urging means and a driving force transmission means of the chair according to the present invention, with FIG. 3(a) illustrating the state when the chair is not in use and FIG. 3(b) illustrating the state when the chair is in use.

EMBODIMENT OF THE INVENTION

Hereinafter, with reference to the drawings, the embodiment(s) of the chair according to the present invention will be described. It should be noted that some parts are not necessarily congruent with the actual product in order to facilitate understanding of the drawings because the sizes and measurements of some parts are enlarged.

FIG. 1 is a perspective view illustrating an example of the chair according to the present invention, with FIG. 1(a) illustrating an example having one main leg and FIG. 1(b) having two main legs. In FIGS. 1, 10, 20 denote a chair, 11, 21 denote a seating face, and 12, 22 a, 22 b denote a main leg. Here, the chair is depicted in the state of self-standing; however, the chair is characterized in that it lacks stability against gravity, easily falls, and has two or less points of contact of the main leg with the face on which the main leg is placed, namely, with a floor or ground surface.

FIG. 2 is a drawing illustrating an example of the chair according to the present invention having one main leg provided with auxiliary legs, with FIG. 2(a) illustrating the state when the chair is not in use and FIG. 2(b) illustrating the state when the chair is in use. In FIGS. 2, 13 denotes an auxiliary leg attached part, 14 a, 14 b denote auxiliary legs, and 15 denotes a slip resistance. Here, only two auxiliary legs are depicted; however, another auxiliary leg is provided on the rear face of the drawing. In other words, three auxiliary legs are evenly arranged around the main leg at angles of 120°. As described herein, according to the chair of the present invention, the front end of the auxiliary leg comes into contact with the face on which the auxiliary leg is placed when the chair is not in use, while the front end of the auxiliary leg is separated from the face on which the auxiliary leg is placed when the chair is in use.

When the main leg is also used for self-standing, it is clear that only two auxiliary legs are required. Moreover, slip resistance 15 is desirably attached as it is difficult for the user to maintain their balance if the front end of the main leg easily slips against the face on which the main leg is placed. As the material of the slip resistance, rubber with flexibility and a large friction coefficient, etc. is desirable.

FIG. 3 is a cross-sectional view illustrating an example of the configurations of an urging means and a driving force transmission means of the chair according to the present invention, with FIG. 3(a) illustrating the state when the chair is not in use and FIG. 3(b) illustrating the state when the chair is in use. In FIGS. 3, 16 denotes a compression coil spring of the urging means, 17 denotes a rotary shaft, 18 a denotes a gear provided on the auxiliary leg side as a driving force transmission means, and 18 b denotes a gear provided on the main leg side.

As illustrated in FIG. 3, according to the chair of the present invention, when the weight of the user is not loaded onto the seating face, coil spring 16 becomes substantially completely extended. Due to the engagement of the gear, the front end of auxiliary leg 14 a is arranged at the bottom of the drawing. When the weight of the user is loaded onto the seating face, main leg 12 moves in the direction against the urging force of coil spring 16, with the front end of auxiliary leg 14 a arranged at the top of the drawing. Thereby, the chair supports the weight of the user with only one main leg.

As described above, the present invention provides a chair that can stand by itself when not in use despite having one or two main legs. While an example is not specifically illustrated, a length adjustment mechanism can be provided to the main legs of the chair according to the present invention, in addition to potentially attaching a caster at the front end of the auxiliary legs.

Moreover, according to the abovementioned example, while a compression coil spring is used as the urging means, an extension coil spring can be used depending on the arrangement of the urging means; further, a volute spring can also be used. In other words, the present invention is not limited to the abovementioned embodiment(s). The present invention may include various design changes including various deformations and modifications that are made without departing from the scope of the invention and are obvious to those skilled in the art of the present invention.

EXPLANATION OF THE SYMBOLS

10, 20 . . . chair

11, 21 . . . seating face

12, 22 a, 22 b . . . main leg

13 . . . auxiliary leg attached part

14 a, 14 b . . . auxiliary leg

15 . . . slip resistance

16 . . . compression coil spring

17 . . . rotary shaft

18 a, 18 b . . . gear 

1. A chair, comprising a seating face and one or two main legs that are attached to the bottom of the seating face substantially vertical to the seating face and at least two auxiliary legs that are attached via a rotary shaft provided around the main leg, with the front end on the opposite side of the part attached to the rotary shaft capable of being rotated within the face including the main leg, wherein the front end of the auxiliary leg at the opposite side of the part attached to the rotary shaft comes into contact with the face on which the chair is placed due to the effect of an urging means and a driving force transmission means attached to the main leg when the weight of the user is not loaded, while the front end of the auxiliary leg on the opposite side of the part attached to the rotary shaft is separated from the face on which the chair is placed when the weight of the user is loaded.
 2. The chair according to claim 1, wherein the length of the main leg can be adjusted.
 3. The chair according to claim 1, wherein a slip resistance is provided at the end on the opposite side of the part of the main leg attached to the seating face.
 4. The chair according to claim 1, wherein the front end of the auxiliary leg on the opposite side of the part attached to the rotary shaft is provided with a caster. 